Cancer is now the biggest target disease for gene therapy protocols worldwide. Despite significant advances in the treatment of cancer in the last two decades, most tumors remain resistant to all current treatment modalities – surgery, radiotherapy, chemotherapy, and biotherapy. Local methods such as surgery and radiotherapy are often only effective in the absence of metastatic disease. Despite tremendous effort over the last fifty years, only a very small proportion of human cancers are cured by chemotherapy.

Gene-based therapy is a novel therapeutic approach to treating cancer which has been made possible only by recent and remarkable progress in our understanding of the molecular biology of cancer. Gene therapy can be described as the transfer to human cells and the expression of genetic material for a therapeutic purpose. Currently there are over two hundred gene therapy protocols active worldwide specifically aimed at single gene defects such as cystic fibrosis and a growing number of cancers. This book outlines the diverse approaches being attempted to develop effective future cancer therapies.

The last decade has seen dramatic advances in our understanding of the mechanisms involved in the control of cell growth and their deregulation in cancer. Certain classes of genes encode proteins that play distinct roles in the processing of signals from the outside of the cell to the nucleus. Any changes to the delicate system of control by these oncogenes or tumor suppressor genes may result in the formation of cancer.